U.S. Pat. No. 5,241,940 (Gates, Jr.) and U.S. Pat. No. 5,613,479 (Gates et al.), which are hereby incorporated by reference, disclose EGR systems of the type in which a module that embodies principles of the present invention is useful. The inventive module possesses a novel construction that provides important economic and functional advantages relating to fabrication, assembly, testing, installation, and use.